What is segmental duplication genetics?

Segmental duplications (also termed “low-copy repeats”) are blocks of DNA that range from 1 to 400 kb in length, occur at more than one site within the genome, and typically share a high level of (>90%) sequence identity (reviewed by Eichler [2001]).

How common are segmental duplications?

We found that approximately 4% of the genome is covered by duplications and that the extent of segmental duplication varies from 1% to 14% among the 24 chromosomes. Intrachromosomal duplication is more frequent than interchromosomal duplication in 15 chromosomes.

What is segmental deletion?

Chromosomal segmental deletion is a frequent cause of human disease. Such chromosomal microdeletion regions span a few Mb genomic DNA sequences and contain multiple genes. Deletion of multiple genes often leads to haploinsufficiency syndromes.

Do segmental duplications contain genes?

In 98% of CMT1A a segmental duplication of one chromosome including the PMP gene is present, giving, in total, three copies of the gene.

What is the purpose of multigene families?

The term multigene families is used to include groups of genes from the same organism that encode proteins with similar sequences either over their full lengths or limited to a specific domain. DNA duplications can generate gene pairs.

Which of the following genetic syndrome is also known as mongolism?

Down syndrome, also called Down’s syndrome, trisomy 21, or (formerly) mongolism, congenital disorder caused by the presence in the human genome of extra genetic material from chromosome 21.

What is deletion and duplication?

Homologous recombination between areas of concentrated repeated sequences frequently creates deletions and duplications. Because they commonly involve more than one gene, the disorders caused by these large deletion and duplication mutations are often severe.